Re: Tools for those working heavily with strings

[Arash Esbati]

carlmarcos--- via Users list for the GNU Emacs text editor 
<help-gnu-emacs@gnu.org> writes:

> What can I use to test whether a string in composed of whitespace or
> is empty?

I'm not sure if I understand the "composed of whitespace" part
correctly, but you can try:

(let ((s "With space"))
  (and (string-match " " s)
       (message "With space")))

(let ((s "    "))
  (and (string-match "\\`[[:space:]]*\\'" s)
       (message "Only spaces")))

(let ((s ""))
  (and (string= s "")
       (message "Empty string")))

(let ((s ""))
  (and (= (length s) 0)
       (message "Empty string")))

Best, Arash